Internal combustion engines, including diesel engines, gasoline engines, natural gas engines, and other engines known in the art, may exhaust a complex mixture of air pollutants. The air pollutants may be composed of gaseous compounds and solid particulate matter, which may include unburned carbon particles called soot.
Due to increased attention on the environment, exhaust emission standards have become more stringent and the amount of particulates emitted from an engine may be regulated depending on the type of engine, size of engine, and/or class of engine. One method that has been implemented by engine manufacturers to comply with the regulation of particulate matter exhausted to the environment has been to remove the particulate matter from the exhaust flow of an engine using a particulate trap. A particulate trap is a filter designed to trap particulate matter in, for example, a mesh filtering media. Such a fine mesh filter media, designed to entrap small particulate matter, may saturate quickly with both large and small particulate matter, resulting in undesirable exhaust system back pressure. A coarse wire mesh filter media, designed to only trap large particulate matter without increasing exhaust system back pressure, however, may allow the smaller particulate matter to be exhausted to the atmosphere.
One method of trapping both large and small particulate matter within the same particulate trap without creating undesirable exhaust flow restriction is described in U.S. Pat. Ser. No. 5,557,923 (the ‘923 patent) issued to Bolt et al. on Sep. 24, 1996. The ‘923 patent describes a device for removing particulates produced by internal combustion engines that includes an electrode for electrostatically charging the particulates. The charged particulates are attracted to and trapped within an electrically grounded fine-mesh filter. A current is passed through the filter at regular intervals causing the filter material to heat to a temperature above the combustion temperature of the particulates (i.e., regeneration).
Although the device of the ‘923 patent may reduce the number of large and small particulates exhausted to the environment without increasing exhaust system back pressure, the device may require large amounts of energy during regeneration. The large amounts of energy may require large power producing components and power circuitry. As a result, initial cost as well as operational costs of the engine system utilizing the device may be expensive.
The disclosed particulate trap is directed to overcoming one or more of the problems set forth above.